package com.csbook.restaurant;import javax.swing.UIManager;import java.awt.*;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: </p> * @author pengtao * @version 1.0 */public class Main {  boolean packFrame = false;  private LoginSystem loginSys=null; //Construct the application public Main() {   loginSys = new LoginSystem();   //Validate frames that have preset sizes   //Pack frames that have useful preferred size info, e.g. from their layout   if (packFrame) {     loginSys.pack();   }   else {     loginSys.validate();   }   //Center the window   Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();   Dimension frameSize = loginSys.getSize();   if (frameSize.height > screenSize.height) {     frameSize.height = screenSize.height;   }   if (frameSize.width > screenSize.width) {     frameSize.width = screenSize.width;   }   loginSys.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);   loginSys.setVisible(true); } public static void main(String[] args) {    try {      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());    }    catch(Exception e) {      e.printStackTrace();    }    new Main();  }}